255516665 has 4 divisors (see below), whose sum is σ = 306620004. Its totient is φ = 204413328.

The previous prime is 255516661. The next prime is 255516671. The reversal of 255516665 is 566615552.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 100240144 + 155276521 = 10012^2 + 12461^2 .

It is a cyclic number.

It is not a de Polignac number, because 255516665 - 2² = 255516661 is a prime.

It is a super-4 number, since 4×255516665⁴ (a number of 35 digits) contains 4444 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (255516661) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 25551662 + ... + 25551671.

It is an arithmetic number, because the mean of its divisors is an integer number (76655001).

Almost surely, 2^255516665 is an apocalyptic number.

It is an amenable number.

255516665 is a deficient number, since it is larger than the sum of its proper divisors (51103339).

255516665 is an equidigital number, since it uses as much as digits as its factorization.

255516665 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 51103338.

The product of its digits is 270000, while the sum is 41.

The square root of 255516665 is about 15984.8886452174. Note that the first 3 decimals coincide. The cubic root of 255516665 is about 634.5605614876.

The spelling of 255516665 in words is "two hundred fifty-five million, five hundred sixteen thousand, six hundred sixty-five".